Sleepless Nights, Nesting Turtles and Rising Seas

We can’t really be sure in this individual case. But, we can be fairly confident that sea level rise will affect nesting sea turtles, if it hasn’t already. The question isn’t whether the seas will rise. The question is if the sea turtles can adapt.We're here in Dominica, in the middle of the night, hiding out in a hut on the edge of a beach. It's windy and rainy, and we're all exhausted.

But, we're also excited. Thanks to support from Disney's Friends for Change Project Green, we are about to increase our knowledge of the gigantic leatherback sea turtle. Perhaps even more exciting is the fact that we're going to be able to share this all with local (and international) students by using satellite technology. At a half hour to midnight on our second night here, we saw our first sea turtle. We were thrilled. This was what we’d been waiting for. This was why we were here.

The plan was simple. We would hang back and watch while the female turtle crawled past the waves and dug her nest in the sand. We would wait until she began to lay her eggs, at which point she would enter a trance-like state and would be oblivious to us. That would be our moment. We’d quickly measure the length and width of her shell, make a few notes on her apparent health, and attach a small satellite tag to the back of her shell. Then, we’d slip back into the shadows and watch as she finished laying her eggs, cover the nest with sand and return to the waters of the Atlantic Ocean.

The satellite tag would cling painlessly to her back for at least six months (possibly longer), and would send occasional signals back to us on shore. We would learn something about leatherback sea turtle migration patterns, and would share it all with some of the fifth grade students enrolled in Floating Classroom in nearby communities. It would be the perfect opportunity to show these Dominican students how far “their” sea turtles traveled, and to illustrate how very interconnected the world is.

That was the plan. Things didn’t work out as planned. The turtle did settle down to dig a nest. But, the spot she chose was too close to the water. Every time she used a flipper to scoop sand out of the nest, another wave would crash around her, filling the hole with sand and seawater. She dug for about an hour before finally giving up and returning to the water. We hope she’ll return tomorrow. I’m actually glad she didn’t stick around to lay her eggs. Sea turtles dig their nests safely above the high tide line, where the eggs will be safe from pounding waves and rough storms.

If she had actually laid her eggs — possibly as many as 100 — in that nest, they almost certainly would have all been destroyed long before a hatchling could develop. But why was she digging so close to the ocean? She wasn’t a first-time mother — by her flipper tag we identified her as a turtle who we know successfully laid eggs here in 2009. Was it just a mistake? A fluke? Or, something worse? We’ve really got no way of knowing what happened with this particular turtle. But, recent studies do point to something that can cause trouble for nesting sea turtles soon, if not already.

More severe storms: Beach erosion is the main threat here, especially if storms hit in the summer months, when sea turtle eggs are incubating in beachfront nests.

Hotter sands: Sea turtle gender is determined by the temperature of the sand where the egg is incubated. Hotter beaches mean that more eggs could develop into females, causing a potential shortage of male sea turtles.

Sea level rise: Some predictions suggest that sea level could rise more than half a meter before the end of this century. That’s a lot of prime sea turtle nesting territory that will soon be underwater.

Changing currents: Research suggests that climate change could actually redirect or slow major ocean currents, which could disrupt sea turtle migrations and the distribution of their food.

Have the seas risen here in Dominica enough to confuse this turtle? Is that why she built her nest too close to the ocean? Because the ocean stretched further onto the beach than it did in 2009? Perhaps. We can’t really be sure in this individual case. But, we can be fairly confident that sea level rise will affect nesting sea turtles, if it hasn’t already. The question isn’t whether the seas will rise. The question is if the sea turtles can adapt. Only time will tell. -- JL